Polycarbonate resins are polymers obtained by combining aromatic or aliphatic dioxy compounds by means of a carbonate. Out of these, a polycarbonate resin obtained from 2,2-bis(4-hydroxyphenyl)propane (commonly called “bisphenol A”) (may be referred to as “PC-A” hereinafter) is used in many fields because it has high transparency and heat resistance and excellent mechanical properties such as impact resistance.
Polycarbonate resins are generally manufactured from raw materials obtained from oil resources. The depletion of oil resources is now apprehended, and a polycarbonate resin obtained from an ether diol manufactured from sugar which is biogenic matter is under study. For example, an ether diol represented by the following formula (a) is easily made from sugar or starch and three stereoisomers of the ether diol are known.
More specifically, they are 1,4:3,6-dianhydro-D-sorbitol (to be referred to as “isosorbide” hereinafter in this text) represented by the following formula (b), 1,4:3,6-dianhydro-D-mannitol (to be referred to as “isomannide” hereinafter in this text) represented by the following formula (c), and 1,4:3,6-dianhydro-L-iditol (to be referred to as “isoidide” hereinafter in this text) represented by the following formula (d).

Isosorbide, isomannide and isoidide are obtained from D-glucose, D-mannose and L-idose, respectively. For example, isosorbide can be obtained by hydrogenating D-glucose and dehydrating it with an acid catalyst.
Particularly a polycarbonate resin obtained from isosorbide as a monomer out of the above ether diols has been studied.
For example, patent document 1 proposes a homopolycarbonate resin having a melting point of 203° C. which is manufactured by a melt transesterification process. Non-patent document 1 proposes a homopolycarbonate resin having a glass transition temperature of 166° C. and a thermal decomposition temperature (5% weight loss temperature) of about 283° C. which is manufactured by the melt transesterification process using zinc acetate as a catalyst. Non-patent document 2 proposes a homopolycarbonate resin having a glass transition temperature of about 144° C. which is manufactured from a bischloroformate of isosorbide by interfacial polymerization. Patent document 2 proposes a polycarbonate resin having a glass transition temperature of 170° C. or higher which is manufactured by using a tin catalyst. Patent document 3 proposes a copolycarbonate resin obtained from isosorbide and a linear aliphatic diol.
When the industrial application of these polycarbonate resins obtained from isosorbide is taken into consideration, the impact resistances of these resins must be improved. For example, the ISO179 notched Charpy impact strength of an isosorbide homopolycarbonate resin having a specific viscosity of 0.33 is about 6 kJ/m2. This value is unsatisfactory for their industrial application and must be improved.
Since impact resistance greatly depends on the molecular weight (=specific viscosity) of a resin in general, to improve the impact resistance, the molecular weight of the resin must be increased. The isosorbide polycarbonate resins disclosed by the patent documents 1 and 2 and the non-patent documents 1 and 2 described above have a problem that when their molecular weights are increased, the melt viscosities of the resins become too high, thereby making it difficult to mold them.
Patent document 4 proposes a resin composition obtained by adding an addition polymer such as ABS resin to an isosorbide polycarbonate resin. Although impact resistance is improved by adding the ABS resin, heat resistance inherent in the polycarbonate resin greatly deteriorates.
(patent document 1) English Patent Application No. 1079686(patent document 2) WO2007/013463(patent document 3) WO2004/111106(patent document 4) JP-A 2007-070438(non-patent document 1) “Journal of Applied PolymerScience”, 2002, vol. 86, p. 872-880(non-patent document 2) “Macromolecules”, 1996,vol. 29, p. 8077-8082